Wireless communication devices have developed over the years in the wake of evolving technology. Earlier, wireless communication devices operated in the Analog Mobile Phone System (AMPS) protocol, and later graduated to the Global System for Mobile Communication (GSM) protocol. The need for increased capacity, higher data speeds, and new service capabilities in wireless communication devices have resulted in the evolution of GSM-based Second Generation (2G/2.5G) architecture into Third Generation (3G) architecture. 3G architecture uses Universal Mobile Telecommunication Systems (UMTS) as communication protocol. 3G architecture/UMTS enables service operators to provide broader services, while supporting a larger number of clients.
Existing wireless communication devices such as cellular telephones, laptops, digital computers and messaging devices can operate at different frequency bands to cater to the frequency requirements of different geographical locations. The wireless communication devices can operate in combination as well. Wireless communication devices can provide multiple services such as satellite, radio and television signal communication. It is desirable for wireless communication devices to be capable of accommodating different transmit and receive frequencies, in order to operate at different frequency bands. In addition, there is a demand for diversity reception for UMTS signals.
This may create a requirement for the wireless communication devices to possess an antenna system having a main radiator, and one or more co-located secondary radiators for transmitting signals and receiving signals.
A wireless communication device may have a plurality of antenna systems. For instance, a first antenna system may be a local antenna system, which is permanently integrated with the existing wireless communication devices, while a second antenna system may be connected to the wireless communication device by conduction through transmission cable. The first antenna system may suffer from the limitation of digital noise interference while operating with the wireless communication device At such instances, transmission is switched over to the second antenna system. The second antenna system may be a remote antenna system acting as an alternative solution to the local antenna system in a weak signal range, or when digital noise emitted by the wireless communication device is increased to a level close to the desired signal level by the local antenna system. The second antenna system may be connected with the wireless communication device either through interconnecting signal cable. The second antenna system may also act as a peripheral that plugs into the wireless communication device.
To each of the local and remote antenna system, the presence of two separate radiators within the antenna system can lead to interference in the signals between the two radiators. General arrangement of the radiators may not allow proper isolation of signals between the radiators. Lack of proper isolation between the signals introduces disturbances to signals conveyed by the radiators. Further, hardware requirements for isolating the signals may increase the device cost.
In addition, wireless communication devices graduating to 3G architecture require that the second radiator is attached separately to satisfy inter-radiator isolation or the diversity correlation. Attaching the second radiator separately entails complex operations and also affects the working of the wireless communication devices.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.